Electrical distribution system



July 27, 1937. w. H. FRANK ET AL ELECTRICAL mswmsunou SYSTEM Filed Sept.24, 19:54

3 Sheets-Sheet 1 IHIIIIIIIIML' u INVENTORS WA, ATT RNEY.

y 1937- w. H. FRANK ET AL 2,088,105

ELECTRICAL DISTRIBUTION SYSTEM Filed Sept. 24, 1934 s Shets-Sheet 2 1VENTORS BY- 59 I)- EMMATTORNEY.

July 27, 1937. w, H, FRANK AL 2,088,105

ELECTRICAL DISTRIBUTION SYSTEM Filed Sept. 24, 1934 3 Sheets-Sheet 3INVENTOR.

ATTORNEY.

Patented July 27, 1937 ELECTRICAL DISTRIBUTION SYSTEM William H. Frankand Joseph W. Harper, Detroit, Mich., assignors to Bulldog ElectricProducts Company, Detroit, Mich a corporation of West VirginiaApplication September 24, 1934, Serial Nb. 745,300

'5 Claims.

This application relates to bus duct type electrical distributionsystems and more particularly relates to a novel current take-ofi meansused in connection with bus ducts.

The objects and features of the inventions of this case will be morespecifically described at a later stage of this specification, for anunderstanding of which reference may be had to the appended drawings,which show an embodiment of these inventions.

In these drawings, Fig. 1 shows a safety switch plug in top plan view;

Fig. 2 shows it in side view;

Fig. 3 shows it in end view and on a duct;

Fig. 4 shows it in top plan view with the cover removed for purposes ofclarity;

Fig. 5 shows a detail of the handle locking means;

Fig. 6 is a fragmentary side view of the safety switch plug,particularly showing the plug contacts;

Fig. 7 shows the same in fragmentary top plan view; and

Fig. 8 shows the same in fragmentary end view.

In Figs. 1-8 there is shown a plug which is in the nature of a safetyswitch plug, the plug having an externally accessible handle foroperating the within-contained safety switch parts for switchingoperation; connector and contact details thereof are also shown.

The safety switch plug comprises a sheet metal plug box Illl having anopen bottom and sides provided with downwardly extending portions I I Ifor embracing the sides of the duct l5 with which the plug is to beassociated for guiding and grounding purposes, these portions havingflanges I I2 for engaging the duct flanges II, whereby the duct bolts I6may be utilized to secure the safety switch plug in place on the duct.

Disposed within the plug box at one end thereof is a contact block II2ahaving downwardly projecting contacts or prongs I I3 for engagement withthe bus bars 5|! of the bus duct, the contacts being shielded by tubes Il3a. The box also has knockouts Ill at suitable portions thereof foradmitting branch circuit cables into the interior of the box, whichcables are electrically connected, in the box, to the contacts I I3through a. connection block, a fused safety switch of a character aboutto be described, and the contact block itself.

Disposed within the plug box 0, at the end thereof opposite the contactblock MM is the cable connection block I I 5 aforesaid to which thebranch circuit cables II6 are directly connected, the bared terminalsII! of these cables being fastened, through connectors II8 to straps N9of the connection block. The straps I I9 are contained in individuallybarriered cells I20 of the connection block and are provided with fuseclips I 2|.

Also within the box, but between the contact block 212 and theconnection block M5 is a switch block I22 having individual cells i23corresponding in number to the cells I23 of the connection block H5, andthese are provided with fuse clips I24 which are connected to the fuseclips I2I of the connection block I I5 by conventional fuses I25. Thefuse clips I24 of the switch block I22 are mounted on straps I26 whichare provided with stationary switch contacts adapted to be electricallyconnected to other stationary switch contacts on the switch blockthrough the medium of. a multipole quick makeand-break switchmanipulated by a handle I29 which is accessible externally of the plug,by virtue of the fact that a portion thereof projects through a slot I33in a hinged cover I3I of the plug box III]. The last-mentioned set ofstationary switch contacts are electrically. connected by connectionstraps I32 to the plug contacts I I3 of the contact block II2a.

It will thus be seen that the switch can be manipulated for electricallyconnecting the branch circuit cables II6 to the plug contacts I I3 inthe intended manner and for the purposes for which the safety switchplug is constructed.

For' insuring the safety operation of the switch, that is to say forpreventing the switch from be-. ing thrown when the cover is open, andfor preventing the cover from being opened when the switch is on, aninterlock bar I34 is provided to cooperate with the switch handle. Oneend of the bar is pivotally mounted at I35 in a lug I36 secured to theside of the box III), and the other end is disposed in a guide I3'Isecured to the other side of the box; a spring I38 is wound around thepin'at the pivotal axis I35 of the interlock bar for directing the bartowards the switch handle I29 and for urging the bar to be disposed,whenever possible, in a slot I39 of the handle.

When the cover is open the interlock bar is urged into the slot of thehandle and thus prevents the handle from being rotated to on position.When the cover is closed, the wedgeshaped lug I4I on the cover displacesthe interlock bar from engagement with the handle, 'allowing freeaction. Furthermore with the cover closed and with the handle in "onposition, a portion of the handle overlies a portion of the cover andprevents the cover from being swung open.

A spring latch I42 projects upwardly from the box through a slot 3 inthe cover and cooperates with the cover to hold it latched in closedposition, even when the switch handle is in "of! position, the latchbeing manipulable to permit the cover to be opened when the switch is"oif.

The interlock bar is provided with a thin sheet I of insulation whichoverlies a major part of the switch and conceals it, thus insuringagainst accidental contact with the live side of the switch when fuseremoval and insertion is being effected with the cover open.

The handle I29 and the latch I42 are provided with suitable aperturesfor the reception of padlock bails whereby the switch handle and theswitch cover may be locked in place for desired purposes.

- Now having described the invention, we therefore claim the following:

1. Electrical distribution systems comprising bus duct runs formed oftubular closed duct runs containing insulatedly mounted naked bus runsand having entrance holes on one of their walls providing access totheir bus runs, and elongated branch circuit current take off devicesdisposed outside the duct run and comprising casings con,- tainingcontact prongs projecting therefrom and insertable into the duct runthrough the holes thereof to make contact with the bus runs, and alsocontaining-connectors and protective means for branch circuit conductorswhich enter the devices through walls thereof, the devices havingextensions on their side walls cooperating with complementary formationsof the duct run sides for detachably securing the devices to the ductrun, with the devices disposed outside the duct run, and for guiding thedevices into cooperating engagement with the duct runs as they are beingmoved towards the duct run, the extensions being arranged to meet theduct run before the prongs reach the bus runs and to leave the duct runafter the prongs leave the bus runs to ground the devices, to the ductrun before electrical contact between the contacts and the busruns isestabllshed and to ground the devices to the duct runs after suchcontact is broken.

2. Electrical distribution systems comprising bus duct runs formed oftubular closed duct runs containing insulatedly mounted naked bus runsand having entrance holes on one of their walls Providing access totheir bus runs, and elongated branch circuit current take off devicescompris-' 8 cup shaped casings closed on all sides except one, which oneis open, the casings containing contact prongs projecting from theiropen sides and insertable into the duct run through the holes thereof tomake contact with the bus runs, and also containing connectors andprotective means for branch circuit conductors which enter the devicesthrough walls thereof, the devices having extensions on their side wallscooperating with complementary formations of the duct run sides fordetachably securing the devices to and for guiding the devices intocooperating enga ment with the duct runs, the prongs, connectors, andprotective means being accessible through the open sides of the devices,normally closed by the adjacent duct run walls and in sealed relationtherewith, the extensions being arranged to meet the duct run before theprongs reach the bus runs and to leave the duct run after the prongsleave the bus runs to ground the devices to the duct run beforeelectrical contact between the contacts and the bus runs is establishedand to ground the devices to the duct runs after such contact is broken.

3. Electrical distribution systems comprising bus duct runs formed oftubular closed duct runs containing insulatedly mounted naked bus runsand having entrance holes on one of their walls providing access totheir bus runs, and elongated branch circuit current take of! devicescomprising cup shaped casings closed on all sides except one,which oneis open, the casings containing contact prongs projecting from theiropen sides and insertable into the duct run through the holes thereof tomake contact with the bus runs, and also containing connectors andprotective means for branch circuit conductors which enter the devicesthrough walls thereof, the devices having extensions on their side wallscooperating with complementary formations of the duct run sides fordetachably securing the devices to and for guiding the devices intocooperating engagement with the duct runs, the prongs, connectors,

and protective means being accessible through the open sides of thedevices, normally closed by the adjacent duct run walls and in sealedrelation therewith, the extensions being arranged to meet the duct runbefore the prongs reach the bus runs and to leave the duct run after theprongs leave the bus runs to ground the devices to the duct run beforeelectrical contact between the contacts and the bus runs is establishedand to ground the devices to the duct runs after such contact is broken,the devices having switching means formed as parts thereof whereby thebranch circuits may be switched to and from the bus runs even when thedevices are supported by the duct runs, and even while their prongsengage the bus bars.

4. Electrical distribution systems comprising bus duct runs formed oftubular closed duct runs containing insulatedly mounted naked bus runsand having entrance holes on one of their walls providing access totheir bus runsyand elongated branch circuit current taken off devicescomprising cup shaped casings closed on all sides except one, which oneis open, the casings containing contact prongs projecting from theiropen sides and insertable into the duct run through the holes thereof tomake contact with the bus runs, and also connectors and protective meansfor branch circuit conductors which enter the devices through wallsthereof, the device having extensions on their side walls cooperatingwith complementary formations of the duct run sides for detachablysecuring the devices to the duct runs, the prongs, connectors, andprotective means being accessible through the open sides of the devices,normally closed by the adjacent duct run walls and in sealed relationtherewith.

5. Electrical distribution systems comprising bus duct runs formed oftubular close duct runs containing insulatedly mounted naked bus runsand having entrance holes one one of their walls providing access totheir bus runs, and elongated branch cvircuit current take oil? devicescomprising cup shaped casing closed on all sides except one, which oneis open, the casings containing contact prongs projecting from theiropen sides and insertable into the duct run through the holes thereof tomake contact with the bus runs, and also connectors and protective meansfor branch circuit conductors which enter the dcvices through wallsthereof, the devices having extensions on their side walls cooperatingwith complementary formations of the duct run sides for detachabiysecuring the devices to the duct runs, the prongs, connectors, andprotective 5 means being accessible through the open sides of deviceshaving switching means formed as parts thereof whereby the branchcircuits may be switched to and from the bus runs even when the devicesare supported by the duct runs, and even while their prongs engage thebus bars.

JOSEPH W. HARPER.

